Total Dissolved Solids(TDS) are the total weight of all solids(minerals, salts, or metals) that are dissolved in a given volume of water, express in milligrams per liter(mg/L), or in parts per million(ppm).

pH is a unit of measure which describes the degree of acidity or alkalinity of a solution. It is measured on a scale from 0 to 14.

The orP is an important water chemistry parameter, providing a measurement of the oxidizing and reducing capacity of water.